1. Disease Control and Health Emergency Program, World Health Organization Vietnam Country Office, Ha Noi, Vietnam
2. Epidemiology Department, Pasteur Institute Nha Trang, Nha Trang, Vietnam
3. Department of Communicable Disease Control, National Institute of Hygiene and Epidemiology, Ha Noi, Vietnam
4. General Department of Preventive Medicine, Division of Communicable Disease Control, Ha Noi, Vietnam
5. Binh Thuan Provincial Centre of Disease Control, Binh Thuan, Vietnam
6. Nam Dinh Provincial Centre of Disease Control, Nam Dinh, Vietnam
7. Department of Community Health, School of Health Sciences, Tohoku University Graduate School of Medicine, Sendai, Japan